Pololu Blog (Page 6)

Welcome to the Pololu Blog, where we provide updates about what we and our customers are doing and thinking about. This blog used to be Pololu president Jan Malášek’s Engage Your Brain blog; you can view just those posts here.

Cedarville University Solar Boat Team

Posted by Ryan on 6 March 2017

A technical paper about hydrofoil design by members of the Cedarville University Solar Boat Team won a $1,000 Honorable Mention in the 2016 Mandles Prize for Hydrofoil Excellence from the International Hydrofoil Society. The boat they’ve been building uses a few Pololu Jrk 12v12 USB motor controllers to drive linear actuators that control the hydrofoil angle of attack which controls the boat’s flight. (Yes, flight: a hydrofoil boat uses wing-like hydrofoils that lift up the hull as they “fly” through the water.) They plan to enter this boat in the “Top Class” of the Dutch Solar Challenge. The “Top Class” provides entrants the opportunity to design every aspect of their solar-powered boat, which they will use in a series of sprint and endurance races over the course of five days. They also plan on racing in the Solar1 Solar Boat World Championship at the Yacht Club de Monaco.

Science Olympiad 2017 robot arm competition

Posted by Ryan on 3 March 2017

Congratulations to Matthew Siracusa and William Rule who placed first in the Robot Arm competition of the Science Olympiad SE PA Regional Tournament last Wednesday! They used our custom laser cutting service to cut the base and structural components of the robot arm out of black ABS. We wrote about another one of Matthew’s projects on this blog when he made a 6-string banjo (that has a frame we also laser cut) as part of the 2014 Science Olympiad.

The Science Olympiad website has more information about the Robot Arm competition.

Steel custom laser cutting available

Posted by Arthur on 2 March 2017

We’ve been offering quick-turn custom laser cutting service ever since “we” were just Candice and Jan operating a tabletop Epilog out of their home. Since then we’ve cut a wide assortment of customer designs including jewelry, engraved control panels, robot chassis, Christmas ornaments, and wedding invitations.

We started out mostly cutting acrylic, gradually moving into cutting a wider variety of plastics and wood. All along we’ve been improving our processes and increasing our capabilities by buying machines with bigger beds, better control systems, and more power. Without announcing it officially, we’ve been cutting metal for customers and ourselves over the past few years. For example, we cut our Basic Sumo Blade for the Zumo Chassis and the SMT stencils for our in-house electronics assembly. We’ve been refining our metal cutting processes and finding the best cut settings to minimize the chance of burring and dross, so most parts come out relatively clean and smooth to the touch.

The process quality has gotten to the level where we are comfortable announcing that metal laser cutting is generally available to customers!

Through cutting, vector etching, and raster engraving on stainless steel.

Through cutting, vector etching, and raster engraving on mild steel.

Through cutting, vector etching, and raster engraving on spring steel.

Top-side scan of laser-cut stainless steel.

Top-side scan of laser-cut mild steel.

Top-side scan of laser-cut spring steel.

Bottom-side scan of laser-cut stainless steel.

Bottom-side scan of laser-cut mild steel.

Bottom-side scan of laser-cut spring steel.

You can see in the pictures above that laser-cut steel parts have a slight discoloration along the laser-cut edges caused by the chemical reaction that takes place when cutting. Depending on the steel type and whether the cuts are through the material, vector-etched line art, or raster-engraved filled-in areas, the discoloration is different (some tend to be brownish while others are a dark gray). We do not guarantee that parts will be free of blemishes; we ship the parts without any post processing, and we currently do not offer additional services such as deburring, tumbling, or bending.

As stocked materials (shown on our quote request page), we carry #304-2B stainless steel in 0.024″, 0.030″, 0.036″, 0.048″, 0.060", and mild steel in 0.030″ and 0.060″. We can arrange to use material you ship to us, but keep in mind that steel is the only metal we can cut. We cannot cut copper, brass, titanium, aluminum, or precious metals.

To get started on having your laser-cut steel parts cut, submit a quote request here.

Web-based control of a telescope using Raspberry Pi

Posted by Brandon on 1 March 2017

@MarcisShadow is working on a project using a Raspberry Pi with a Pololu DRV8835 Dual Motor Driver Kit for Raspberry Pi to control a Celestron NexStar GoTo Mount, allowing web-based control of a telescope. He also uses a Pololu 5V Step-Up/Step-Down Voltage Regulator S7V7F5 connected to the motor driver to power the Raspberry Pi from the motor power supply.

The project is being documented in a multi-part series on DirtyAstro.com. Part 1 covers the electronics that come with the telescope mount, part 2 is about assembling and testing the DRV8835 driver kit and motors, part 3 tackles setting up the Raspberry Pi and using an SSH client (PuTTY) to connect to it remotely via a PC, and part 4 is about getting Node-Red running to program the Raspberry Pi graphically using a web interface from any machine on the network.

He is not finished with the project, but I have a couple of suggestions for him or anyone doing something similar: First, since his 12 V supply exceeds the maximum operating voltage of both the motor driver (11 V) and the regulator (11.8 V), I would recommend using different ones. Keep in mind that “wall-wart” DC power supplies, especially older transformer-based ones, can have a voltage significantly higher than the rated voltage. Second, a board running a full operating system is usually not great for timing-sensitive operations like counting encoder ticks. If it can’t keep up with the pulse rate, I would recommend using a secondary microcontroller for the encoders. One possibility would be to use the A-Star 32U4 Robot Controller SV with Raspberry Pi Bridge, which incorporates a more appropriate 5.5 V – 36 V regulator, an Arduino-compatible microcontroller, and dual motor controllers.

New distributors in the Americas

Posted by Ryan on 28 February 2017
Tags: distributors

Last week, I wrote about our new distributors in Europe. We’ve also added some new distributors in the Americas since our last round of new distributor introductions:

Chicago Electronic Distributors are a new distributor in—you guessed it— Chicago, USA. They offer a variety of Pololu products for sale on their website and free shipping on US orders over $100. They prefer customers buy directly from their website, but they also have an eBay and Amazon store.

FlexRC is an online store in Canada that specializes in multi-rotor drones. They sell a couple of our voltage regulators alone and as part of kits. Search “pololu” on their website to see all their products with Pololu regulators. They have over 50 quadcopter videos on their YouTube channel.

ElectroStore joins our five other distributors in Ecuador. They are based in Quito and Riobamba, but they ship all over the country. Their product selection is available on their Facebook page, and you can contact them to place an order, or you can order through MercadoLibre Ecuador.

Smart Electronics Projects is an online electronics store in Lima, Peru. They sell a variety of Pololu products including motors drivers, encoders, gearmotors, and wheels. They also offer courses in robotic and electronics design, and provide 3D printing, laser cutting, and design services.

CPIDI Vava – Technologies is an online store also in Lima, Peru, bringing the total number of distributors in Peru to three! They carry a selection of Pololu metal gearmotors, wheels, and other products you can see in their Pololu category.


See the full list of over 200 distributors to find one in your area.

Animatronic C-3PO replica

Posted by Ryan on 27 February 2017

This animated C-3PO replica, made by one of our customers, moves its eyes, arms, head, and—in true C-3PO fashion—tells tasteless jokes. The movements are animated by a Pololu Mini Maestro 18-channel USB servo controller. A Pololu RC switch with relay (controlled by the Maestro, not an RC transmitter) shuts off the power to the head to avoid servo humming noises. (You can achieve a similar result with most servos by not sending RC servo pulses, which a Maestro does when the servo target is zero.)

The customer’s C-3PO web page has more videos and extensive documentation on how the replica was built.

RC multiplexer for quadcopter operator mode switching

Posted by Ryan on 24 February 2017

One of our customers, “Bartman” on the dronevibes.com forum, has made a video of himself planning his build and a forum post that explains how he built his quadcopter. He was inspired by the DJI Inspire 1, which raises its struts to get them out of the camera’s way. Bartman proposes a lighter and cheaper arrangement: when flying the quadcopter in its semi-autopilot “carefree” mode, he switches yaw control from the pilot to the camera operator. This gives the camera operator panning (via the entire copter’s yaw motion) without the need for a separate panning mechanism. He uses a Pololu RC multiplexer to achieve the control switching.

A close-up of the RC mux on Bartman’s multi-rotor.

More details and discussion are in the forum thread.

Automatic rotating arcade cabinet display

Posted by Ryan on 23 February 2017

Customer Raph Koster made this slick automatic rotating arcade cabinet display, which allows the arcade cabinet to easily switch from landscape to portrait depending on the game. The monitor is rotated by a servo controlled by a Micro Maestro 6-Channel USB Servo Controller. The Maestro is especially convenient for this type of project, because you can connect it to the computer using USB then control the servo using our command line utility usccmd.

Raph shares his usccmd scripts for automating the rotation along with a full parts list and extensive step-by-step build information in his forum post at ArcadeControls.com.

TwoPotatoe and ThreePotatoe compete at AVC

Posted by Grant on 22 February 2017

I am happy to bring some overdue attention to our customer who created TwoPotatoe, a balancing robot that I first wrote about on this blog a few years ago. This past fall, TwoPotatoe and his new robot ThreePotatoe competed in the Sparkfun AVC Competition. TwoPotatoe won first place for the 10 lb to 25 lb weight class. Check out the AVC video below! TwoPotatoe starts its run at about 53:00. ThreePotatoe won second place in the 25 lb to 40 lb weight class. Considering all the weight classes together, TwoPotatoe and ThreePotatoe scored third and fourth place overall, which is very impressive considering they were competing against four-wheeled robots that didn’t have to balance. ThreePotatoe’s run starts at about 1:08:30.

You can find more pictures and information about TwoPotatoe and ThreePotatoe in the AVC competition on the TwoPotatoe website.

GoonieBox: a puzzling piece of interactive furniture

Posted by Ryan on 22 February 2017

Customer Guido Bonelli Jr., who is also the creator of the Dr.Duino Arduino shield, had us laser cut pieces of baltic birch for a unique piece of furniture for his home: a large, interactive puzzle. An Arduino Mega 2560 R3 controls the various puzzles and contraptions packed into this piece. His article in Design News goes into more detail including a parts list and more pictures.

New Products

Addressable RGB 150-LED Strip, 5V, 5m (SK9822)
Addressable RGB 8x32-LED Flexible Panel, 5V, 10mm Grid (SK9822)
FEETECH High-Torque Servo FS5115M
Wall Power Adapter: 5.25VDC, 2.4A, 20AWG MicroUSB Cable
Addressable RGB 60-LED Strip, 5V, 2m (SK9822)
Sanyo Pancake Stepper Motor with Encoder: Bipolar, 200 Steps/Rev, 42×31.5mm, 5.4V, 1 A/Phase, 4000 CPR
Free Circuit Cellar magazine April 2017
Aluminum Standoff for Raspberry Pi: 11mm Length, 4mm M2.5 Thread, M-F (4-Pack)
Addressable RGB 16x16-LED Flexible Panel, 5V, 10mm Grid (SK9822)
Verbal Machines VM-CLAP1 Hand Clap Sensor
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